Method of cleaning an hvac air duct

ABSTRACT

An improved apparatus for cleaning ducts of a heating/ventilation/air conditioning (HVAC) system is provided. In one embodiment, the present invention comprises a pod having a vacuum chamber therein, a drive motor located within the pod and configured to receive a removable drive shaft therein, and a conduit member located within the pod adjacent the drive motor. The conduit member has a vacuum inlet opening at an exterior wall of the pod and a drive shaft exit opening formed in the conduit member through which the removable drive shaft can extend. In one embodiment, the invention comprises a man-portable pod and a cart removably-coupleable to the man-portable pod. A method of manufacturing the apparatus and a method of cleaning an HVAC duct is also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a Divisional of U.S. application Ser. No. 10/860,469filed on Jun. 2, 2004, entitled “AIR DUCT CLEANING APPARATUS,” commonlyassigned with the present invention and incorporated herein byreference.

TECHNICAL FIELD OF THE INVENTION

The present invention is directed, in general, to an air duct cleaningsystem and, more specifically, to an improved air duct cleaning systemfor removing dust and debris from air conditioning and heating ducts,dryer vent ducts, etc., of residential and commercial buildings.

BACKGROUND OF THE INVENTION

So called “house dust” is widely considered by experts to pose healthhazards to persons with allergies, asthma, or respiratory disorders anddiseases. House dust may contain dirt, textile fibers, pollen, hair,skin flakes, residue of chemical and household products, cat and dogdander, decaying organic matter, dust mites, bacteria, fungi, viruses,and a variety of other contaminants. Literally, pounds of house dustaccumulate on vents and in ducts that comprise the ventilating systemsof both residential and commercial buildings. This house dust isbecoming increasingly more harmful as Americans spend a largerpercentage of their waking hours indoors, often aggravating allergies ofthe inhabitants.

Modern heating/ventilating/air conditioning (HVAC) systems typicallyincorporate air filters either just prior to the circulation fan of thesystems or in the return ductwork. However, most often these filterscomprise fiberglass or similar media that are reasonably effectiveagainst large debris, but are often inadequate in removing fineparticulate matter, such as dust, dander, etc., from the circulated air.Such filters may trap as little as twenty percent of the particulatematter circulating in a ventilation system, allowing the remaining dustand debris to circulate in the household or work place. A considerableafter-market industry has flourished providing both active and passiveelectrostatic air filters. However, such filters only address thoseparticles in the air that pass through them after being returned fromthe living space. The filter does not affect dust and debris that isalready present in the ducts downstream of the HVAC unit that may bedisturbed by airflow and carried into the living space. Additionally, itis not uncommon to encounter ductwork that has been improperly installedor maintained. These ducts frequently leak, allowing dust and debrisfrom the duct surroundings to enter the ducts. Often this is a majorcontributor to duct contamination.

Prior to the invention of duct vacuuming systems, one method ofaddressing this problem was by sealing the dust and debris to the innerwalls of the ducts by coating it with a layer of a water-based resin,known in the trade as “duct sealer” or “soot sealer”. This compound iscommonly used in fire restoration of ventilating systems. Afterphysically cleaning and sealing the outflow registers, a hole is cut inthe duct of the ventilating system. An electric misting fogger is thenmounted over the hole. The fogger is activated and the soot sealer isdispersed throughout the ventilating system. The soot sealer forms acoating over the inner walls of the entire duct system, encapsulatingdust and other harmful impurities. Thus, the dust is not removed fromthe system, but rather the sealant forms a new interior duct surfacewith the dust trapped between the duct wall and the sealant surface.This method has several inherent limitations. However, the drawbacks tothis system are its cost and the fact that the water based soot sealer,given the right humidity conditions, may dissolve, thereby freeingtrapped dust and debris.

A more recent approach to the problem of debris in ventilation ducts hasbeen to use a rotating brush at the end of a flexible vacuum hose thatis fed into each duct from each register location. The hose is fedtoward the outflow portion of the HVAC system to the limit of the hoselength. Practically speaking, the hose is usually about 25 feet to 35feet long. Additionally, the vacuum-generating units of these systemshave been quite large and, while mobile, were of such a size and weightthat they are impracticable to take into an attic. Yet, because ofexcessively long ductwork, it has sometimes been necessary to makemultiple entries along the duct system in order to completely clean theducts. It is sometimes impractical to properly clean the ducts of modernhomes with high, two-story ceilings with this system. Most of theavailable hose would be used just to reach a register that is 15 to 18feet above the floor. Extending the hose by using additional lengths wasdifficult because of the need to also extend the brush drive mechanismthroughout the additional lengths of the hose. Additionally, theseconventional systems, due to their general configurations, may make itdifficult to position the duct cleaning machine close to the systembeing cleaned in order to maximize use of available hose.

Accordingly, what is needed in the art is an apparatus that offers amore flexible and mobile approach for cleaning HVAC ducts.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies of the prior art, thepresent invention provides an improved apparatus for cleaning ducts of aheating/ventilation/air conditioning (HVAC) system. In one embodiment,the present invention comprises a pod having a vacuum chamber therein, adrive motor located within the pod and configured to receive a removabledrive shaft therein, and a conduit member located within the podadjacent the drive motor. The conduit member has a vacuum inlet openingat an exterior wall of the pod and a drive shaft exit opening formed inthe conduit member through which the removable drive shaft can extend.The conduit member further includes a curve along an air path centerline of the conduit member, wherein the curve has an obtuse angle takenfrom a center line normal to the vacuum inlet opening.

In another aspect, the present invention comprises a man-portable podhaving a vacuum chamber and a motor therein, a conduit member locatedwithin the man-portable pod and a cart removably-coupleable to theman-portable pod. The conduit member has a vacuum chamber end and avacuum hose end and an air path therebetween. The vacuum chamber end isin fluid communication with the vacuum chamber and the vacuum hose endis coupleable to an end of a flexible vacuum hose. The cart isconfigured to provide rollable conveyance for the man-portable pod andattached hose including up and down stairs. A method of manufacturingthe apparatus and a method of cleaning an HVAC duct is also provided.

The foregoing has outlined preferred and alternative features of thepresent invention so that those skilled in the art may better understandthe detailed description of the invention that follows. Additionalfeatures of the invention will be described hereinafter that form thesubject of the claims of the invention. Those skilled in the art shouldappreciate that they can readily use the disclosed conception andspecific embodiment as a basis for designing or modifying otherstructures for carrying out the same purposes of the present invention.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference isnow made to the following descriptions taken in conjunction with theaccompanying drawings, in which:

FIG. 1A illustrates a top off-angle perspective view of one embodimentof an improved apparatus for cleaning ducts of a heating/ventilation/airconditioning (HVAC) system;

FIG. 1B illustrates an exploded view of the air duct cleaner showing theman-portable pod and the cart individually

FIG. 2A illustrates a left side view of one embodiment of the majorinternal elements of the man-portable pod;

FIG. 2B illustrates a front oblique view of the major internal elementsof the man-portable pod of FIG. 2A;

FIG. 2C illustrates a rear view of the major internal elements of theman-portable pod;

FIG. 3A illustrates a rear elevation view of the conduit member of FIG.2 including a hose attachment having the vacuum inlet openingtherethrough and located at a vacuum hose end of the conduit member;

FIG. 3B illustrates a rear elevation view of the conduit member of FIG.2 with the hose attachment shown in FIG. 3A removed;

FIG. 3C illustrates a sectional view of the conduit member along plane3C-3C shown in FIG. 3B;

FIG. 4 illustrates a front oblique view of the hose attachment;

FIG. 5 illustrates a rear oblique view of the major internal elements ofthe man-portable pod and indicating an airflow path through/around themajor internal elements; and

FIG. 6 illustrates a flow diagram for a method of cleaning aresidential/commercial HVAC system having an outflow plenum.

DETAILED DESCRIPTION

Referring initially to FIGS. 1A and 1B, illustrated is a top off-angleperspective view of one embodiment of an improved apparatus 100 forcleaning ducts of a heating/ventilation/air conditioning (HVAC) system.For the purposes of this description, the apparatus 100 will henceforthbe referred to as an air duct cleaner 100. It should be understood thatwhile the present discussion is directed to HVAC ducts, the sameequipment and principles may also be used to clean other duct systems,e.g., dryer vent ducts, etc. The air duct cleaner 100 comprises twoprinciple elements: a man-portable pod 110, which is easily removablefrom a cart 120. FIG. 1B illustrates an exploded view of the air ductcleaner 100 showing the man-portable pod 110 and the cart 120individually. Additionally, a flexible vacuum hose 140 having aninternal flexible drive shaft 145, a vacuum nozzle 147, and a generallydomal-shaped brush 150, are coupleable to the man-portable pod 110. Onewho is of skill in the art is familiar with the flexible vacuum hose 140and brush 150 and their application to duct cleaning.

In a preferred embodiment, the cart 120 is configured to providerollable conveyance for the man-portable pod 110 and the flexible vacuumhose 140. The cart 120 comprises a cart body 121; forward-mounted casterwheels 122 (only one visible); rear-mounted fixed wheels 123; left andright rear fenders 124, 125, respectively; left and right front posts126, 127, respectively; a handle 128; a slot 131; and a first portion132 a of a latch 132. In one embodiment, the latch 132 may be a barrelbolt. In a preferred embodiment, the cart body 121 is made from a wellknown durable, light weight molded plastic. In a preferred embodiment,the cart body 121, left and right rear fenders 124, 125, respectively;and left and right front posts 126, 127, respectively; are molded as asingle piece. The left rear fender 124 of the cart 120 has a groove 129on an upper surface thereof. Furthermore, the cart 120 has a declivity130 from the left rear fender 124 toward the left front post 126 locatedon a left front corner of the cart 120. Both the groove 129 and thedeclivity 130 are sufficiently wide to support at least a portion of theflexible vacuum hose 140 for coiled storage. The groove 129 is presenton the left rear fender 124 to provide a guide to an operator as theflexible vacuum hose 140 is coiled around the pod 110 while connected toa vacuum inlet 111 of the man-portable pod 110. Likewise, the left andright front posts 126, 127, respectively, are positioned a distance dfrom the man-portable pod 110 and are spaced sufficiently to receive thevacuum hose 140 therebetween. As such, the pod 110 serves as storage forthe coiled vacuum hose 140, when the man-portable pod 110 is coupled tothe cart 120. The vacuum inlet opening 111 is proximate an exterior wall115 of the man-portable pod 110 and is located higher up the exteriorwall 115 than the prior art. This provides a better arrangement of thehose 140 that may now remain coiled about the man-portable pod 110 andenables the air duct cleaner 100 to more conveniently be rolled up anddown stairs than the prior art.

In a preferred embodiment, the man-portable pod 110 is also made of thesame durable and light weight molded plastic as the cart body 121. Theman-portable pod 110 comprises: a handle 112, a rear shelf 113, a topcover 114, a cleat 116; and a second portion 132 b of the latch 132. Thecleat 116 is configured to cooperate with the slot 131 in the forwardportion of the cart 120 to help secure the man-portable pod 110 to thecart 120. Furthermore, the first portion 132 a and the second portion132 b of the latch 132 cooperate to removably couple the man-portablepod 110 to the cart 132. The handle 112 is coupled to the man-portablepod 110 structure and configured to enable a technician to lift andcarry the man-portable pod 110 unattached from the cart 120, as shown inFIG. 1B. The rear shelf 113 is configured to support at least a portionof the flexible vacuum hose 140 for coiled storage between theman-portable pod 110 and the cart handle 128 when the man-portable pod110 is coupled to the cart 120. The top cover 114 provides a technicianwith access to the interior of the man-portable pod 110 for changingdisposable elements therewithin.

The unique configuration of the detachable man-portable pod 110 and thecart 120 allows for the man-portable pod 110 to be easily removed fromthe cart 120 when tight attic spaces or openings have to be navigated.As such, the main vacuum unit can be taken proximate to the plenum sothat the maximum length of the duct, limited only by available hoselength and not by HVAC system configuration, can be reached. Therefore,the system provides for a more thorough cleaning of the ventilationduct, as well as a time savings. This is in distinct contrast to theconventional units discussed above where, in many cases, the ventilationducts had to be cleaned from the registers because this unique pod/cartconfiguration was not previously available in the art.

Referring now simultaneously to FIGS. 2A-2C. FIG. 2A illustrates a leftside view of one embodiment of the major internal elements of theman-portable pod 110. FIG. 2B illustrates a front oblique view of themajor internal elements of the man-portable pod of FIG. 2A. FIG. 2Cillustrates a rear view of the major internal elements of theman-portable pod 110. Elements of the duct cleaner 100 reside within theman-portable pod 110 (See FIG. 1B). For example, a debris collection bag211 is positioned in an upper portion of the man-portable pod 110, whichmakes it easily accessible by way of the top cover 114. The debriscollection bag 211 occupies a major portion of a vacuum chamber 212. Adrive motor 213 is also located within the man-portable pod 110 adjacentthe debris collection bag 211 but the drive motor 213 is separated fromthe vacuum chamber 212 by a vacuum chamber wall 212 a. A conduit member214 extends from an outer wall of the man-portable pod 110 to the debriscollection bag 211, and as explained below has a unique configurationthat allows for greater air flow, and thus, greater vacuum efficiency.

First and second vacuum motors 215 a, 215 b are located underneath thedebris collection bag 211 outside of the vacuum chamber and are coupledto first and second filters 216 a, 216 b, respectively. Moreover, theyare configured to create a vacuum in the vacuum chamber 212. The filters216 a, 216 b are held in place by first and second filter catches 217 a(only the first filter catch 217 a is visible), which allows for easyremoval of the filters from the man-portable pod 110. An electronicscontrol board 218 is strategically positioned under the drive motor 213,which allows air from the vacuum motors 215 a and 215 b to cool theelectrical components on the board. A friction clutch 219 is coupled toa drive wheel 220 and a drive shaft 221 and these components combine todrive a flexible drive shaft in the a vacuum tube that is not shown.Those who are skilled in the art will understand how an end of aflexible drive shaft may be configured to couple to the drive shaft 221.In a preferred embodiment, the drive motor 213 is a bidirectional drivemotor 213.

In a preferred embodiment, the two vacuum motors 215 a, 215 b areemployed in order to increase airflow through the system. The first andsecond filters 216 a, 216 b, are located within the vacuum chamber 214and are removably coupleable to the first and second vacuum motors 215a, 215 b, respectively. In a preferred embodiment, the first and secondfilters 216 a, 216 b comprise HEPA filters having a high filteringcapacity. Additionally, they are one-third larger (longer) than filtersused in previous duct cleaning apparatus. This allows for greaterairflow through the filters while using the same power of vacuum motoras in previous systems. The first and second filter catches 217 a, arecoupled to the man-portable pod 110 and are located proximate the firstand second filters 216 a, 216 b. The first and second filter catches 217a are configured to hold the first and second filters 216 a, 216 b, tothe first and second vacuum motors 215 a, 215 b, respectively.

Moreover, the filters 216 a, 216 b and filter catches 217 a, 217 b areconfigured to enable a technician to rapidly change the filters 216 a,216 b, yet hold the filters 216 a, 216 b securely against the first andsecond vacuum motors 215 a, 215 b. The first and second filter catches217 a, 217 b are physically identical and in a preferred embodiment,comprise flat spring steel bent to a profile as illustrated with a tab231 and a bend 232. Removal of the respective filter 216 a or 216 b isaccomplished by pulling the tab 231 toward a front of the pod 110 untilthe bend 232 clears a forward end 235 of the filter 216 a or 216 b. Thefilter 216 a or 216 b may then be rotated upwardly and decoupled at arear end 236 from the respective vacuum motor 215 a or 215 b. A newfilter 216 a or 216 b may then be installed by placing the rear end 236proximate the respective vacuum motor 215 a or 215 b and rotating thenew filter 216 a or 216 b downwardly until bend 232 snaps into place onthe forward end 235.

Referring now simultaneously to FIGS. 3A-3C for various views of theconduit member 214 of FIG. 2. FIG. 3A illustrates a rear elevation viewof the conduit member 214 of FIG. 2, including a vacuum hose attachment310 having the vacuum inlet opening 111 therethrough and located at avacuum hose end 331 of the conduit member 214. Note that the conduitmember 214 lies at an angle a from a vertical reference line 320. FIG.3B illustrates a rear elevation view of the conduit member 214 of FIG. 2with the hose attachment 310 shown in FIG. 3A removed. Clearly shown isan opening 330 of the conduit member 214 at the vacuum hose end 331 andproximate the vacuum inlet opening 111. FIG. 3C illustrates a sectionalview of the conduit member 214 along plane 3C-3C shown in FIG. 3B. Theconduit member 214 also has a vacuum chamber end 332 that is coupleableto the debris collection bag 211.

The conduit member 214 has formed therein an air path 310 that is influid communication with the vacuum chamber 212 and has an air pathcenter line 311 that is a curve 311. The curve 311 forms an obtuse angle312 taken from a center line 313 normal to the opening 330 and thevacuum inlet opening 111. In a preferred embodiment, the obtuse angle312 is about 139°. The conduit member 214 also has a drive shaft exitopening 314 formed in the conduit member 214 through which a removableflexible drive shaft (not shown) coupled to a rotatable brush (notshown) can extend. As can be seen in FIGS. 3A and 3C, the air pathcenter line 311 forms a compound curve 311 in that it includes twogently angled turns, as shown in FIG. 3C, and the plane of thecenterline 311 is offset from the vertical at an angle a. The obtuseangle of the compound curve provides advantages over right-angled priorart configurations in that the curved path allows for a greater airflow,thereby providing for greater vacuum. In addition, the gentle curvatureof the conduit member 214 allows for greater component density andstrategic location of those components within the man-portable pod 110.For example, the gentle curvature of the conduit member 214 allows forthe close placement of the drive motor 213 and drive wheel 220, while,at the same time, providing for a less restricted airflow path withinthe man-portable pod 110.

The drive shaft exit opening 314 is configured to receive the removableflexible drive shaft of the rotatable brush therein. By forming theconduit member 214 as shown, the flexible drive shaft will exit theconduit member 214 low in the opening 330 as far as possible from theair path centerline 311. This placement, as compared to prior art whichexited the flow path at approximately the air path centerline, allowsminimal curving of the air path 310 to clear the drive shaft exitopening 314 and the drive wheel 220. Furthermore, as can be seen in FIG.3B, the conduit member air path opening 330, preferably has an ovoidcross section.

Referring now to FIG. 4, illustrated is a front oblique view of the hoseattachment 310. The hose attachment 310 has a conduit member end 401 anda hose end 402. The conduit member end 401 has a cross sectional shapenecessary to couple to the opening 330 of the conduit member 214 (SeeFIG. 3B). In the illustrated embodiment, both the cross sectional shapeand the opening 330 are ovoid. This contrasts to a circular crosssection of the hose end 402. Three rivets 411, 412, 413 enablepush-and-twist coupling of the vacuum hose 140 to the hose end 402.

It should be noted that a cross sectional area of the conduit member end401 is substantially greater than a cross sectional area of the hose end402. In a preferred embodiment, the cross sectional area of the conduitmember end 401 is about two times the cross sectional area of the hoseend 402.

Referring now to FIG. 5, illustrated is a rear oblique view of severalof the internal elements of the man-portable pod 110. An airflow path510 is indicated by the arrows through and around the internal elements.The man-portable pod 110 further comprises an AC power connector 501, amaster power switch 502, and a mini-DIN receptacle 503. The AC powerconnector 501 is configured to accept a removable three-conductor110-115 VAC equipment power cord (not shown for clarity). The mini-DINreceptacle 503 accepts a conventional mini-DIN plug 504 electricallycoupled to a remote control 505.

The electronic board 218 is mechanically coupled to a bottom cover 507of the man-portable pod 110 proximate the drive motor 213 and positionedwith respect to the first and second vacuum motors 215 a, 215 b toreceive cooling air therefrom as shown by the airflow path 510. Theelectronics board 218 is electrically coupled to: the AC power connector501; the master power switch 502; the mini-DIN receptacle 503; theremote control 505; the drive motor 213; and the first and second vacuummotors 215 a, 215 b, respectively. The remote control 505 uses only lowvoltage AC, i.e., <1.0 VAC, electrical power derived from the 110/115VAC power by the electronics board 218. This is in contrast to prior artthat routinely uses 110/115 VAC line power at the remote controls ifthey are so equipped. The use of low voltage AC electrical power ispreferred for improved component reliability of the electronics board.The circuitry of the electronic board 218 is configured to power OFF theair duct cleaner 100 if the mini-DIN plug 504 becomes disconnected fromthe mini-DIN receptacle 503. The air duct cleaner 100 cannot be poweredup without connecting the mini-DIN plug 504 to the mini-DIN receptacle503.

The electronic board 218 is electrically configured to regulate one ormore operations of the first and second vacuum motors 215 a, 215 b orthe drive motor 213. Specifically, the electronic board 218 isconfigured to start the three motors 213, 215 a, 215 b in sequence sothat the air duct cleaner 100 can be readily used on commonly availableelectrical power on lighting circuits of homes and businesses, i.e.,110/115 VAC from a duplex wall outlet rated at 15 amps. One who isskilled in the art is familiar with the fact that electric motors have ahigher amperage draw during startup than the amperage required for asteady running state. The electronic board 218 accomplishes sequentialstartup of the entire system by starting only one motor at a timethereby limiting the startup amperage draw to that of only one AC motorat a time. In most situations, it is advisable to start the vacuummotors first, because if either or both of the vacuum motors areinoperative, it is not desirable to run the drive motor with a brush ina duct to prevent drive cable failure.

In practice, a start switch 521 on the remote control 505 is pushed.This starts a sequence of events on the electronic board 218 that startsthe first vacuum motor 215 a which is sized to be as powerful aspossible without exceeding a total current draw of all three motors of15 amps. When the first vacuum motor 215 a is running stable, theelectronic board 218 automatically continues the startup sequence bystarting the second vacuum motor 215 b. Only when both vacuum motors 215a, 215 b are running stable, does the electronic board 218 enablestarting the drive motor 213. After startup, the electronic board 218 isable to keep the total current draw at all times below 15 amps,typically not exceeding 14.09 amps. This prevents repeated tripping ofthe circuit breaker that would be common if all three, or even any two,of the motors were started simultaneously.

The electronic board 218 further includes a drive motor 213 reversingfunction. That is, the electronic board 218 may be commanded to reversethe rotational direction of the drive motor 213 with a drive motorswitch 522 on the remote control 505. The drive motor switch 522 hasthree positions: ON(CW)-OFF-ON(CCW). As stated above, once the secondvacuum motor 215 b is running normally, the drive motor switch 522 isenabled. Placing the drive motor switch 522 to ON(CW) causes theelectronic board 218 to start the drive motor 213 to run with aclockwise rotation. Conversely, placing the drive motor switch 522 toON(CCW) causes the electronic board 218 to start the drive motor 213 torun with a counter-clockwise rotation. The electronic board 218 hasadditional circuitry that causes the drive motor 213 to come to a “FullStop” whenever the drive motor switch 522 is moved to or passes throughthe OFF position. This prevents the drive motor 213 from being rapidlyreversed, or accidentally stopped and then rapidly re-engaged, in orderto protect the drive motor 213.

The electronic board 218 further includes a Maintenance Only test killfunction. That is, connections on the electronic board 218 toselectively allow start and stop of either of the vacuum motors 215 a,215 b, independently of the operation of the other vacuum motor. Thisenables a technician to isolate a vacuum motor failure. This functionoperates independently of the drive motor 213 circuitry and is notaccessible with the air duct cleaner 100 in its normal operatingconfiguration.

It should be noted that the combination of: (a) exit location of theflexible drive shaft, (b) increased cross sectional area of the conduitmember end 401 versus the hose end 402, (c) less abrupt change ofdirection of the air path flow, (d) increased size of the HEPA filters216 a, 216 b, and (e) dual vacuum motors 215 a, 215 b each individually,and collectively, contribute to an increase in air flow by about 18 to20 percent at the hose nozzle 147 (See FIG. 1A), thus improving vacuumefficiency significantly.

It should be noted that the present invention may be used while theman-portable pod 110 is coupled to the cart 120. However, a preferredmethod of operation of the air duct cleaner 100 is to clean a ductsystem from the vicinity of the main outflow plenum of an HVAC systemprior to the first branching of the ducts. Referring now to FIG. 6 withcontinuing reference to FIGS. 1A through 5 as required, illustrated is aflow diagram 600 for a method of cleaning a residential/commercial HVACsystem 600 having an outflow plenum.

The method begins at Start Step 605. At Step 610, the air duct cleaner100 is brought to the site having the HVAC system. At Step 615, theman-portable pod 110 is decoupled from the cart 120. At Step 620, theman-portable pod is positioned proximate the outflow plenum of the HVAC.At Step 625, a service opening is cut or opened in the outflow plenum.At Step 630, a flexible vacuum hose 140 with an internal flexible driveshaft 145 and attached rotary brush 150 is coupled to the vacuum inlet111 and to the drive shaft 221 of the man-portable pod 110. At Step 635,the rotatable brush 150 and portions of the flexible vacuum hose 140 andinternal flexible drive shaft 145 are fed into the outflow plenumthrough the access hole. At Step 640, the Start Switch on the remotecontrol is actuated.

At Step 641, the first vacuum motor 215 a starts. At Step 642, thesecond vacuum motor 215 b starts thereby making full system vacuumavailable. At Step 643, the drive motor 213 is started, thereby rotatingthe rotatable brush. At Step 645, the flexible vacuum 140 and internalflexible drive shaft 145 are directed along the outflow duct collectingdebris from inside of the duct and directing the debris along theflexible vacuum hose 140 to the collection bag. At Step 650, therotatable brush 150 arrives at a branch in the duct. At Step 655, therotatable brush 150 is directed along one branch of the duct system.

At Step 660, the operator decides if the duct being cleaned issubstantially wider than the brush. If the answer is YES, then themethod moves to Step 661 where the drive motor direction is reversed tocause the brush 150 to work against an opposite wall of the duct untilStep 662 when the brush arrives near an outlet register. If the answeris NO, the method proceeds until step 662 when the brush 150 arrivesproximate the outlet register. At Step 663, the operator decides if allof the ducts have been cleaned. If the answer is NO, then the operatorretrieves the brush 150 back to the previous branch of the duct. At thebranch and Step 665, the operator directs the brush 150 along adifferent branch of the duct and the method returns to Step 660. Steps660 through 663 are repeated until all branches have been cleaned. Ifthe answer is YES, then the method proceeds to Step 670 and the brush150 is retrieved to the vicinity of the access hole.

At Step 671, the drive motor 213 is stopped. At Step 672, the operatorremoves the flexible vacuum hose 140 and rotatable brush 150 from theplenum. At Step 675, both vacuum motors 215 a, 215 b are stopped. AtStep 680, the service opening is covered with a removable panel. At Step685, the man-portable pod is returned and coupled to the cart. At Step690, the air duct cleaner is removed from the premises. At Step 695, themethod ends. One who is of skill in the art will recognize thatvariations to the order in which various of the above steps occur arewithin the broad scope of the present invention.

Thus, a duct cleaning apparatus and method of cleaning a duct has beendescribed. The duct cleaning apparatus comprises a man-portable pod thatis removable from a cart designed to provide rollable transport for theman-portable pod and storage for the accompanying vacuum hose.

Although the present invention has been described in detail, thoseskilled in the art should understand that they can make various changes,substitutions and alterations herein without departing from the spiritand scope of the invention in its broadest form.

1. A method of cleaning a heating/ventilation/air conditioning (HVAC)air duct, comprising: providing an apparatus for cleaning ducts of anHVAC system, said apparatus comprising: a man-portable pod having avacuum chamber and a drive motor therein; a conduit member locatedwithin said man-portable pod and having a vacuum chamber end and avacuum hose end and an air path therebetween, said vacuum chamber end influid communication with said vacuum chamber; a flexible vacuum hosehaving a conduit end and a duct end and wherein said flexible vacuumhose has a rotatable brush at said duct end, and wherein said flexiblevacuum hose is coupleable to said vacuum hose end of said conduitmember; and a cart removably-coupleable to said man-portable pod andconfigured to provide rollable conveyance for said man-portable pod; andopening a service opening in a duct of said HVAC system; uncoupling saidman-portable pod from said cart; transporting said man-portable podproximate said service opening; and inserting said flexible vacuum hosethrough said service opening and into said duct.
 2. The method asrecited in claim 1 wherein opening said service opening includes openingsaid service opening proximate an outlet plenum of said HVAC system. 3.The method as recited in claim 1 further comprising coupling saidrotatable brush to said motor and rotating said rotatable brush withsaid drive motor.
 4. The method as recited in claim 3 further comprisingreversing a direction of said rotatable brush with said drive motor. 5.The method as recited in claim 3 further comprising passing saidrotatable brush from said service opening along said duct to an outletregister.
 6. The method as recited in claim 3 further comprisingdislodging debris from an inside of said duct.
 7. The method as recitedin claim 6 further comprising: creating a vacuum within said vacuumchamber; applying said vacuum to said duct end; and collecting saiddebris in a bag within said vacuum chamber.
 8. The method as recited inclaim 1 further comprising: removing said flexible vacuum hose from saidduct through said service opening; and installing a cover over saidservice opening.